Selective and Scalable Aldehyde Production via Partial Oxidation of Alcohols in Acidic Media

While challenging, scalable partial electro-oxidation
of alcohols
to aldehydes presents a sustainable pathway for producing value-added
chemicals along with green hydrogen. Here, we first pinpoint the optimal
electrolyte environment for selective partial oxidation of alcohols, i.e., acidic media, and then develop a CoO–Co3O4 catalyst integrated into an asymmetric proton-exchange
membrane electrolyzer, enabling selective and stable alcohol partial
oxidation. Furthermore, separation of the pure alcohol anolyte from
the aqueous catholyte minimizes competing oxygen evolution and mitigates
metal dissolution. Detailed mechanistic investigations reveal that
the CoO/Co3O4 interface promotes the rate-limiting
first proton-coupled electron transfer step, enabling >95% aldehyde
selectivity and >90% Faradaic efficiency for a broad scope of alcohols.
Encouragingly, the system maintains high selectivity (>90%) toward
aldehyde over other overoxidized products, even at industrially relevant
current densities up to 200 mA cm–2, highlighting
a promising improvement over the conventional aqueous system. Overall,
this strategy provides an effective platform for selective alcohol
oxidation and offers a promising path toward scalable electrosynthetic
technology.